Process for making and molding hard porcelain



Patented May 3, 1927.

UNITED STATES;

* I 1,627,245 PATENT OFFICE.

ARTHUR mansnann mom'rosn, or sxnnnx, aus'rmrn.

PMC1588103 MAKING AND HOLDING m1) PORCELAIN.

Io Drawing.

The object of my invention is to providea new and improved process for making process involves the fusing of porcelain materials or substances and the shaping thereof under pressure. Further, by. my process the use of water and bonding material may be dispensed with.

Certain results are assured which have not been attainable by methods and proc-,

esses heretofore employed, or not attainable in like degree. These results may be briefly described as follows: In respect of physical properties the finished product, when my process is employed, has unusual tensile strength, greater density, and will not chip or crack oif readily under ordinary conditions. Further advantages arise from the fact that the finished product, when a mold is used, is insured a more nearly exact fit.

In making hard porcelain by my proces, a mold is ordinarily essential. This mold may be of metal or some suitable mineral substance. Where it is necessary to fuse. the porcelain or other material in the mold as in the case of dental inlays, shell crowns and dentures, the substance used for the mold must have the same eoefiicient of expansion, as. the substance being formed. Where it is not required that the substance being formed be fused in the mold, it is not essential that the material of the mold have the same coeflicient of expansion as the molded material. 0

other such products a metallic support may be imbedded at the time the insulator is formed, when such support is desirable. This would be impractlcable under methods heretofore employed. I

As previously intimated, water and bonding materials may he used in my process in the discretion of the manufacturen'having in mind the particular operation to beerformed and.,the character of the finis ed roduct desired. If used, it or they will e mixed before fusing in suitable ropor-- tions with the materlal for porce ain or other ceramic substance to be formed.

If the product desired is of the nature of dental inlays and shell crowns, or in any case requiring fusion in a mold, the melain material is-thenput in the mol and .both mold and porcelain material placed in a furnace.

. constant.

chemical and physical chan e g paredby the customary In the case of electricalinsulatorsand Application fled July 15, 1922. Serial Io. 575,887.

011 the other hand, the porcelain material with or without water orbonding material may be placed'as a mass or sheet in the furnace and fused. I

The porcelain may be molded to the desired form by the a plicatidn of pressure at either of four di erent stages:

.First,when the ware is at fusing temperature; second,after the briginal' fusing and when the temperature has been permitted to fall slightly; third,-after the ware has been cooled, and again raised to a temperature slightly below fusing) heat, and, fourth,after the ware has een cooled, and again raised to fusing temperature.

Porcelain materials in the'prooess of fusion become subject to certain chemical and physical change. Some of the ingredients become fluid, while others remain hard and The hard ingredients act as a frame-work, and prevent distortion or colla se of the molded article during firing.

en glass is fused all the ingredients entering mto its composition become fluid. These two conditions constitutethe essen tial distinction between hard porcelain and glass in the process of manufacture, and the which characterizes hard porcelain, an it from glass, is one which invar abl takes place in the fusion of porcelain or the purposes of my process.

In the employment of my material for ma 'ng porcelain .method. That is feldspar, clays,

process, the

to say, pulverized silica,

kaolin or other substances commonly used for making porcelain are mixed together. Water may then be added until the material is of the consistency of milk, or of cream, or of soft putty, dependin upon the charactor of the finished pr not desired and the further ste s to be taken in carrying put the process. ere forming of the article is to be done by the pressure method, which is the principal and essential characteristic of my process, the materials may be p 7 without the admixture of water or bonding material at any stage. i

' 'FWhenever water is employed 1n my proo-' ess "the orcelain may be shaped or molded before fiision. In some cases, the consistency is such that it is simply painted on the interior or exterior of a mold; in others t is poured into a mold, and in others it is mixed to the consistency of putty and may be prethe higher the grade of porcelain, the

pressed to the form desired. Heretoforc, in making hard porcelain, the shape of the finished product has been determined prior to placing it in the furnace, whereas, with my process, the form of the finished product may he changed by the application of pressure with heat, and its physical properties altered and improved.

Heretofore it has been necessary to calculate with the utmost precision the shrinkage or contraction which the material employed will experience in the drying and fusing operations. Great particularity must be exercised in respect of the ingredients employed, both with reference to their character and proportions, and the amount of water added. In my process all shrinkage or contraction is finished before the molding takes place, so that accuracy is obtained both of form and size by the exercise of relatively less care and skill, and with the expenditure of much less time.

The porcelain material is then placed In the furnace and brought to fusing temperature. This temperature will vary according to the relative fusibility of the original ingredients employed, the rule beingtlliat 1g er will be the fusing point. When the ware has reached fusing heat, prwsure ma be applied by means of die members 0 the' form desired for the finished vproduct. After bein allowed to cool, an enamel or glaze may applied in the usual way. Instead of molding when the porcelain material is at fusing heat, the temperature may be allowed to fall slightly below that point, when the substance will still remain pliable or lastic. It will then resemble a bar of stee at malleable heat. When in this condition, pressure may be applied and the substance molded to the desired shape. A third method included in my process is to allow the substance'to cool gradually. It will then be in the form of what'is described as hiscuit porcelain or ware. After such cooling,

the wareimay be reheated until it reaches a temperature below fusing, but to such a point as will render the ware pliable or plastic. In this condition, pressure may also be applied and the shape desired obtained.

A fourth method included in my process is to allow the ware to cool, and then reheat it to fusing temperature, a l i ressure to obtain the desired form y Hg P As an illustration, but without limiting the application of my process in any manner thereto, it may be desired to produce a porcelain cup. B my process, the original procelain materia may be mixed with water if it is desired, or the use of water may be entirely eliminated. The porcelain material may then be placed of fire clay or other refractory material and thewholeplacedinafurnaee. Whenthe in or upon a vessel mass has reached fusing heat, die members of the shape of the cup may then be applied by pressure to the fused substance, and it will be formed to the desired shapc---t-hat of a cup. ()1' the temperature may he allowed to fall slightly, the ware retaining plastic or pliable properties and the molding may he done in like manner. A third course that may be pursued is to take the ware out of the furnace, allow it to cool gradually and completely, when it will be what is known as biscuit porcelain. At any time thereafter this biscuit porcelain may be reheated, and, before reaching the fusing point will resume its plasticity or pliability, and may be molded as in the second method described. The samemethod may be employed as that described in the third example, except that the ware may be raised to actual fusing temperature and the pressure applied.

In addition to the methods previously described and included in my process, porcelain material previously fused or matured may be pulverized and subjected to all the operations as in the case of the original porcelain substances as hereinbefore set out,

pressure being applied in the same manner and under like conditions.

The advantages of my process of making hard porcelain over recesses heretofore employed may be .brie y indicated as follows:

The use of water may be eliminated by my process. The admixture of water occasions the employment of expensive machine skilled manual labor and considerable time. Before fusing the water must be removed, an operation which also requires expensive apparatus, the application of heat, considerable time and skill and relatively large factory space. These result in delay in production and large financial expense. The ability under my rocess to dispense with water necessarily e tages enumerated.

The elimination of bonding materials, made possible b my process, enables a more rapid ating o the porcelain material, thus effecting an economy of time, and where the bonding material, as is true in some instances, causes an increased porosity of the finished product, and porosity is undesirable,

this disadvantage is also removed.

The ability to use porcelain ware. previously fused makes possible the utilization for the manufacture of hi h grade products, broken, misformed and ot erwise imperfect ware. This will effect a large economy of material.

In the processes heretofore employed, contraction is experienced in the porcelain substance at two distinct stages. First: that resulting to the molded article as a whole by the drying out of the water and the consequent consolidation of the particles, and, second: that resulting during the fusion of inates the resultant disadvana greater accuracy bot volume.

the molded article by the contraction of the particles themselves, due to the application of intense heat. In my pr'ocess,'the article is molded after all contraction is completed and this not only expedites the operation, as has been previously intimated, but insures as to shape, size and The application of pressure at the fusing point or at temperatures and under conditions heretofore described, and contemplated in my process and for the purpose of molding, also produces-greater density. the employment of my process, the finishe porcelain may be produced of higher grade and at less cost of both time and money. I

, My process may be practiced with a great variation in details of steps, and for making a mat variety of articles.

or example, porcelain insulators may be made at a reasonable expense, and they have great density and high resistance to electricity.

Dentures and artificial teeth may be made with great accuracy and saving of time by being pressed to shape in proper molds.

I claim as m invention:-

A process or forming porcelain ware comprising the subjection of ordinar finished porcelain to heat until plastic an then simultaneously sulg'ecting the plastic material to pressure an I 'molding it.

Des Moines, Iowa, June 23, 1922.

- ARTHUR MARSHALL MGINTOSH. 

